Large males have fewer water mites (Arrenurus sp.) on the variable bluet (Coenagrion pulchellum) damselfly

2016 ◽  
Vol 94 (5) ◽  
pp. 339-343 ◽  
Author(s):  
Maria Hughes ◽  
Kari M. Kaunisto ◽  
Jukka Suhonen
Keyword(s):  
Life History ◽  
Body Size ◽  
Wing Length ◽  
Good Condition ◽  
Life History Strategies ◽  
Male Body ◽  
Water Mites ◽  
Water Mite ◽  
Immune Systems ◽  
Mite Prevalence

Ectoparasitic water mites of the genus Arrenurus Dugès, 1834 may affect damselflies in different ways, resulting in lower longevity and reproduction success. We studied the variation of water mite occurrence on the variable bluet (Coenagrion pulchellum (Vander Linden, 1823)) damselfly in relation to the host’s sex, location, and wing length, as well as the amount of black pigment on the abdomens of males. In our study, we found that water mite prevalence and abundance were higher on females. Location of the populations did not affect the prevalence of water mites, nor did the colouring of males. The prevalence and abundance of water mites was lower on larger males than on smaller ones. Our results suggest that females are likely to have more water mites due to different behaviour and life-history strategies. According to our results, male body size is a sign of good condition and, thus, of sufficient resources available to be directed to strengthening their immune systems.

scholarly journals Allometry and morphological trait relationship in the sexually dimorphic Chinese dobsonfly, Acanthacorydalis asiatica (Wood-Mason, 1884) (Megaloptera, Corydalidae)

ZooKeys ◽  
2019 ◽  
Vol 854 ◽  
pp. 119-129
Author(s):  
Chengquan Cao ◽  
Pei Yu ◽  
Fumio Hayashi
Keyword(s):  
Body Size ◽  
Male Genitalia ◽  
Wing Length ◽  
The Body ◽  
Sexually Dimorphic ◽  
Male Body ◽  
Male Body Size ◽  
Intermediate Size ◽  
Mandible Length ◽  
Dimorphic Species

Male insects with large weapons such as horns and elongate mandibles would be expected to invest more on such structures than other parts of the body for advantages in male to male competition for mating. In male genitalia, however, intermediate size provides a better fit for more females than small or large sizes, and such a male would leave more offspring regardless of their body size. These predictions were tested using a static allometry analysis between body size and other trait sizes. Acanthacorydalisasiatica is a large dobsonfly (Megalotera) and males have conspicuously large mandibles used as weapons. We examined the hypothesis that the male mandibles of this sexually dimorphic species are sexually selected to enlarge, whereas the male genitalia are stable to be intermediate regardless of a great variation in body size. The results, as predicted, showed positive allometry between male body size and mandible length but negative allometry between male body size and ectoproct length (a male grasping structure). Sperm are transferred through a small spermatophore attached externally to the female genital opening, so it may be evolutionarily unnecessary to develop an enlarged male genital size. In contrast, there may be a trade-off between male mandible size and wing length, because of negative allometry between body size and wing length in males but isometry between them in females.

scholarly journals Age and body size of Rana amurensis from northeastern China

2011 ◽  
Vol 57 (6) ◽  
pp. 781-784 ◽  
Author(s):  
Wei Chen ◽  
Xin Lu
Keyword(s):  
Body Size ◽  
High Altitude ◽  
Northeastern China ◽  
Life History Strategies ◽  
Male Body ◽  
Age At First Reproduction ◽  
Demographic Traits ◽  
Low Altitude ◽  
Delayed Maturation ◽  
Two Parameters

Abstract Age and body size are two important demographic traits that determine the life history strategies of populations and species. We measured these two parameters of Rana amurensis, at a 900 m and a 500 m altitude site in northeastern China. At the two sites, age at first reproduction was 2 years for males and 3 years for females. The maximum age of males and females at the high-altitude site was 6 and 7 years, and 5 and 7 years at the low-altitude population, respectively. Females were significantly larger than males in both populations, due to greater age in both the highand low-altitude sites. Body size of either males or females did not differ significantly between populations; only males showed increased body size at the high-altitude site when age effect was statistically controlled for. The increased cline of male body size may be attributable to delayed maturation of the sex due to a shorter growing season at high altitudes.

Variability in the life history of Unionicola crassipes, a sponge-associated water mite (Acari: Unionicolidae)

1990 ◽  
Vol 68 (6) ◽  
pp. 1227-1232 ◽  
Author(s):  
Heather C. Proctor ◽  
Gordon Pritchard
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Emerging Adults ◽  
Life Histories ◽  
Population Decline ◽  
Early Summer ◽  
Water Mites ◽  
Water Mite ◽  
History Of ◽  
Female Bias

The life history of a member of the widely distributed Unionicola crassipes complex (Acari: Unionicolidae) in a foothills pond in Alberta, Canada, differs from those previously described for this taxon. Two years are required for a female to develop from an egg to an ovipositing adult. Fertilized females overwinter and oviposit in the sponge Eunapius fragilis in early May. Larvae emerge in late May to early June and parasitize chironomids of the genus Tanytarsus. Engorged larvae drop from their insect hosts and return to sponges for the protonymph resting stage. Active, predaceous deutonymphs develop from protonymphs in early summer. Deutonymphs overwinter and enter the tritonymph resting stage, also in sponges, in early May. Summer adults emerge from the tritonymph stage in late May to early June. Males emerge first, but there is an overall female bias to the sex ratio of emerging adults. Growth of sclerotized and unsclerotized parts occurs in adults over the summer, during which time females appear to suffer greater mortality than males, because the sex ratio is 1:1 in September. It is primarily mated females that overwinter for a second time. A population decline in the summer of 1987 was correlated with degeneration of sponges; variation in the life histories of sponge-associated water mites is discussed in light of this correlation.

scholarly journals Residual reproductive value and male mating success: older males do better

2008 ◽  
Vol 275 (1642) ◽  
pp. 1517-1524 ◽  
Author(s):  
Klaus Fischer ◽  
Jana Perlick ◽  
Tobias Galetz
Keyword(s):  
Life History ◽  
Body Size ◽  
Mating Success ◽  
Reproductive Value ◽  
Male Mating ◽  
Male Body ◽  
Male Mating Success ◽  
Residual Reproductive Value ◽  
Sexually Selected Traits ◽  
Older Males

Evolution via sexual selection has traditionally been viewed as isolated from life-history constraints. As additionally reproductive resource allocation in males is underexplored, it is rather unclear how life-history factors have shaped lifetime investment into male sexually selected traits. Against this background, we here investigate male butterfly mating success in relation to age, nutritional status, assay condition and wing damage. As predicted, based on a low residual reproductive value, older males had a considerably higher mating success than younger males. Comparisons between virgin and once-mated males suggest that this pattern is related to age per se rather than differential ratings of the resource receptive female. We found no evidence for male body size or condition being important, supporting the notion that in weaponless animals intrinsic motivation is more important for mating success than the differences in physical properties (such as body size or condition). Flight cage experiments suggest that such differences in motivation may be masked under more natural conditions, where flight performance, having a clear impact on mating success (as evidenced by wing manipulation experiments), is likely to be crucial. We conclude that the life-history perspective is a fruitful one for gaining a better understanding of the evolution of sexually selected characters and the predictions derived from contest theory do also apply to male mating success.

scholarly journals A new maximum body size record for the Berry Cave Salamander (Gyrinophilus gulolineatus) and genus Gyrinophilus (Caudata, Plethodontidae) with a comment on body size in plethodontid salamanders

2018 ◽  
Vol 28 ◽  
pp. 29-38
Author(s):  
Nicholas S. Gladstone ◽  
Evin T. Carter ◽  
K. Denise Kendall Niemiller ◽  
Lindsey E. Hayter ◽  
Matthew L. Niemiller
Keyword(s):  
Life History ◽  
Body Size ◽  
Large Body ◽  
The United States ◽  
Life History Strategies ◽  
Large Individual ◽  
Plethodontid Salamander ◽  
Plethodontid Salamanders ◽  
The Family ◽  
History Of

Lungless salamanders in the family Plethodontidae exhibit an impressive array of life history strategies and occur in a diversity of habitats, including caves. However, relationships between life history, habitat, and body size remain largely unresolved. During an ongoing study on the demography and life history of the paedomorphic, cave-obligate Berry Cave Salamander (Gyrinophilusgulolineatus, Brandon 1965), we discovered an exceptionally large individual from the type locality, Berry Cave, Roane County, Tennessee, USA. This salamander measured 145 mm in body length and represents not only the largest G.gulolineatus and Gyrinophilus ever reported, but also the largest plethodontid salamander in the United States. We discuss large body size in G.gulolineatus and compare body size in other large plethodontid salamanders in relation to life history and habitat.

scholarly journals Within-host competition drives energy allocation trade-offs in an insect parasitoid

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8810
Author(s):  
J. Keaton Wilson ◽  
Laura Ruiz ◽  
Goggy Davidowitz
Keyword(s):  
Life History ◽  
Body Size ◽  
Life History Theory ◽  
Large Body ◽  
Ecological Impacts ◽  
Life History Strategies ◽  
Biological Organization ◽  
Trade Offs ◽  
Wide Range ◽  
Body Sizes

Organismal body size is an important biological trait that has broad impacts across scales of biological organization, from cells to ecosystems. Size is also deeply embedded in life history theory, as the size of an individual is one factor that governs the amount of available resources an individual is able to allocate to different structures and systems. A large body of work examining resource allocation across body sizes (allometry) has demonstrated patterns of allocation to different organismal systems and morphologies, and extrapolated rules governing biological structure and organization. However, the full scope of evolutionary and ecological ramifications of these patterns have yet to be realized. Here, we show that density-dependent larval competition in a natural population of insect parasitoids (Drino rhoeo: Tachinidae) results in a wide range of body sizes (largest flies are more than six times larger (by mass) than the smallest flies). We describe strong patterns of trade-offs between different body structures linked to dispersal and reproduction that point to life history strategies that differ between both males and females and individuals of different sizes. By better understanding the mechanisms that generate natural variation in body size and subsequent effects on the evolution of life history strategies, we gain better insight into the evolutionary and ecological impacts of insect parasitoids in tri-trophic systems.

scholarly journals Scaling the risk landscape drives optimal life-history strategies and the evolution of grazing

2019 ◽  
Vol 117 (3) ◽  
pp. 1580-1586 ◽  
Author(s):  
Uttam Bhat ◽  
Christopher P. Kempes ◽  
Justin D. Yeakel
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Extinction Risk ◽  
Life History Strategies ◽  
Allee Effects ◽  
Resource Distributions ◽  
Stochastic Fluctuations ◽  
Demographic Risk ◽  
Energetic Reserves

Consumers face numerous risks that can be minimized by incorporating different life-history strategies. How much and when a consumer adds to its energetic reserves or invests in reproduction are key behavioral and physiological adaptations that structure communities. Here we develop a theoretical framework that explicitly accounts for stochastic fluctuations of an individual consumer’s energetic reserves while foraging and reproducing on a landscape with resources that range from uniformly distributed to highly clustered. First, we show that the selection of alternative life histories depends on both the mean and variance of resource availability, where depleted and more stochastic environments promote investment in each reproductive event at the expense of future fitness as well as more investment per offspring. We then show that if resource variance scales with body size due to landscape clustering, consumers that forage for clustered foods are susceptible to strong Allee effects, increasing extinction risk. Finally, we show that the proposed relationship between resource distributions, consumer body size, and emergent demographic risk offers key ecological insights into the evolution of large-bodied grazing herbivores from small-bodied browsing ancestors.

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